Got a good Core Building routine? (Read 1186 times)

I'm just getting back into the swing of running again, and have found my downfall in the past has been adding too much too fast...and quit
I've built a 20 mpw+ base again...and want to incorperate some core building 2/3 x's a week.
Any Suggestions...?
Dave

***Check out my site: where I've been, and where I'm going @ releasetherunner.blogspot.com 2008 Philly Trifecta: 10 Mile Broad St Run-5/4 Philly Distance Run HM-9/21 Philly Marathon-11/23 "A goal not written down is only a dream...!"